Fiirsashada Molal. Maxay ka dhigan tahay fiirsashada gaws iyo molal?

Gaws iyo ka-fiirsashada molal, inkastoo magacyada la mid ah, qiimaha way kala duwan yihiin. Farqiga ugu muhiimsan ee ay tahay in go'aaminta xisaabinta fiirsashada molal la sameeyo ma on mugga of xal sida molarity ogaado, halka miisaanka dareeraha ah.

macluumaad guud oo ku saabsan xal iyo milmi ah

xal True loo yaqaan nidaamka dhqaalaha, oo ay ku jiraan in ay ka kooban dhowr ah oo ka kooban, madax banaan midba midka kale ka. Mid ka mid ah iyaga ka mid ah waa dareeraha ah, iyo inta kale waa maadooyin kala diri waxa ku jira. dareeraha waxaa loo arkaa in ay walaxda in xalka taas oo inta badan.

Milmi - walax la waxyaabaha kale si ay u sameeyaan nidaam dhqaalaha - xal kaas oo ay tahay in foomka of atamka shaqsi, udhigo, taagoo ama qayb ka. fiirsashada A - qiyaas ah milmi.

Sidaas awgeed, milmi ee walxaha waa awooda in loo qaybiyo isku qaab qayb hoose oo dhan mugga dareeraha ah.

xal True waxaa loo kala saaraa sida soo socota:

• nooca dareeraha - non-aqueous iyo biyo;
• nooca solute - xal gaasas, acids, alkalis, cusbada, iwm.,
• waayo dhexgalka koronto - electrolytes (walxaha in ay leeyihiin conductivity korontada) iyo non-electrolytes (walxaha aan awood u conductivity korontada);
• fiirsashada - badhxan oo urursan.

The fiirsashada iyo hab ay ra'yi dhiibashada

content fiirsashada wac (miisaanka) walax kala diri ee xaddi gaar ah (miisaanka ama mugga) ee dareeraha ah, ama in mugga a qeexan oo xal guud. Waxaa dhacaya noocyada soo socda:

1. fiirsashada ee danta (muujiyay in%) - waa sheegayaa sida garaam badan oo solute ku jira 100 garaam oo xal.

2. fiirsashada gaws - waa tirada jiirarka garaam halkii 1 liitar oo xal. Waxay muujinaysaa sida badan garaam-u taagoo ku jira 1 liitar oo xal oo ah walaxda.

3. fiirsashada caadiga ah - waa tirada garaam-dhigma halkii 1 liitar oo xal. Waxay muujinaysaa sida badan ku jira isu dhigmaan garaam ee solute ah ee 1 liitar oo xal.

4. fiirsashada molal muujinaysaa jiirarka sida badan oo solute in cadadka per 1 kiilo ee dareeraha.

5.-baadh oo go'aamisa content (in garaam) ee solute kala diri ee 1 mililitir oo xal.

Gaws iyo uruureen molal kala duwan ka soo midba midka kale. Tixgeli sifooyinka gaarka ah.

fiirsashada gaws

formula ee u go'aamiyo:

CV = (v / V), kuna waari dhexdeeda

v - tirada walxaha kala diri mol;

V - mugga guud ee litir xal ama ^m3.

Tusaale ahaan, "0.1 M xal of H ₂ SO _4" waxay muujinaysaa in in 1 litir oo xal sida joogo 0.1 mol (9.8 g) ee sulfuric acid .

fiirsashada molal

Waa in aad had iyo jeer tixgeliyaan xaqiiqada ah in ay isugu soo urureen molal iyo gaws leedahay macnayaal aad u kala duwan.

Waa maxay molal fiirsashada of xalka? formula The waayo, waxaa la go'aaminayo waa:

Cm = (v / m), halkaas oo

v - tirada walxaha kala diri mol;

m - mass ee dareeraha ah, kg.

Tusaale ahaan, qoraalana 0.2 xal M NaOH ka dhigan tahay in in 1 kiilo oo biyo ah (kiiskan, waa dareeraha ah) kala diridda 0.2 mol NaOH.

qaaciidooyinka dheeraad ah lagama maarmaanka u ah xisaabinta

macluumaad badan oo kaabayaal ah yaabaa in loo baahdo si ay u fiirsashada molal waxaa loo xisaabiyaa. Formula, kaas oo noqon kara mid waxtar leh oo lagu xalliyo dhibaatooyinka ugu waaweyn waa sida soo socota.

lacagta la isticmaalay oo ah walaxda ν ogaadaan tiro cayiman oo atamka, electrons, taagoo, udhigo ama waxay qayb ka kale.

v = m / M = N / N A m = V / V, halkaas oo:

• m - mass ee xarunta, g ama kg,
• M - mass gaws, g (ama kg) / mol;
• N - tirada unugyada oo dhisme ah;
• N _A - tirada unugyada dhismaha halkii 1 bar walax, Avogadro joogto ah: ^6,02. October ²³ mol ^{- 1;}
• V - mugga guud ee l ama m ^3;
• V _m - mugga gaws, litir / bar ama ^m3 / mol.

Last xisaabiyaa sida soo socota:

V _m = RT / P, halkaas oo

• R - joogta 8,314 J / (mol ^K.);
• T - heerkulka gaaska, K,
• P - cadaadis gaaska Pa.

Tusaale ahaan ujeedooyinka for molarity iyo molality. hawsha №1

Si loo go'aamiyo fiirsashada gaws ee xal hydroxide potassium in mugga a of 500 ml. xal miisaanka Koh waa loo siman yahay ilaa 20 garaam.

qeexid

mass gaws ee hydroxide potassium waa:

_Koh M = 39 + 16 + 1 = 56 g / mol.

Waxaan ka rajaynaynaa badan hydroxide potassium ku jira xalka:

ν (Koh) = m / M = 20/56 = 0,36 jirjirroolaha.

Waxaan tixgeliyaan in mugga of xal in la muujiyay in litir galay:

500 ml = 500/1000 = 0.5 litir.

Go'aaminta fiirsashada gaws ee hydroxide potassium:

CV (Koh) = v (Koh) / V (Koh) = 0,36 / 0,5 = 0,72 mol / litir.

hawsha №2

Maxaa baaruud xabagta (IV) ku hoos jira xaalad caadi ah (i.e., marka P = 101325 Pa, iyo T = 273 K) waa inay qaataan si ay u diyaariyaan xal sulfurous acid la uruuray of 2.5 mol / litir ee mugga of 5 litir?

qeexid

Waxaanu ku qeexnaa sida acid sulfurous ku jira xalka:

ν (H ₂ SO ₃₎ = CV (H ₂ SO ₃₎ ∙ V (xal) = 2,5 ∙ 5 = 12.5 mol.

rasiidka isla'egta of sulfurous acid uu leeyahay qaab soo socda:

SO ₂ + H ₂ O = H ₂ SO ₃

Sida laga soo xigtay this:

ν (SO ₂₎ = ν (H ₂ SO _3);

ν (SO ₂₎ = 12.5 mol.

Innagoo maskaxda ku hoos jira xaalad caadi ah 1 bar gaas ayaa mugga a of 22,4 litir, mugga hore ee xabagta reer baaruud:

V (SO ₂₎ = ν (SO ₂₎ ∙ 22,4 = 12,5 ∙ 22,4 = 280 litir.

hawsha №3

Si loo go'aamiyo fiirsashada gaws ee NaOH in xal marka ay miisaan jajab, loo siman yahay 25.5%, iyo cufnaanta ah 1.25 g / ml.

qeexid

Aqbalo sida xal muunad in mugga a of 1 litir oo loo ogaado in ay mass:

m (xal) = V (xal) ∙ P (xal) = 1000 ∙ 1,25 = 1,250 garaam.

Waxaan ka rajaynaynaa inta badan saamiga miisaan alkali:

m (NaOH) = (w ∙ m (xal)) / 100% = (25,5 ∙ 1250) / 100 = 319 garaam.

mass gaws of sodium hydroxide loo siman yahay:

M _NaOH = 23 + 16 + 1 = 40 g / mol.

Waxaan ka rajaynaynaa sida hydroxide sodium ku jira tijaabada,

v (NaOH) = m / M = 319/40 = 8 mol.

Go'aaminta fiirsashada gaws of alkali ah:

CV (NaOH) = v / V = 8/1 = 8 mol / litir.

hawsha №4

In biyaha (100 garaam) ayaa kala diri 10 garaam oo cusbo NaCl. fiirsashada dhigay xal (molality).

qeexid

mass The gaws ee NaCl waa loo siman yahay si:

M _NaCl = 23 + 35 = 58 g / mol.

Number NaCl, ku jira xalka:

ν (NaCl) = m / M = 10/58 = 0,17 jirjirroolaha.

Xaaladdan oo kale, dareeraha waa biyaha:

100 garaam oo biyo ah = 100/1000 = 0.1 kg H ₂ O in xalka.

fiirsashada Molal oo xal u noqon doona loo siman yahay si:

Cm (NaCl) = v (NaCl) / m (biyaha) = 0,17 / 0,1 = 1,7 mol / kg.

hawsha №5

Go'aaminta fiirsashada molal 15% NaOH xal alkali.

qeexid

15% xal alkali ka dhigan tahay in kasta 100 garaam oo xal ka kooban yahay 15 garaam oo NaOH iyo 85 garaam oo biyo ah. Ama in in kasta oo 100 kilo oo xal leedahay 15 kg NaOH iyo 85 kg biyo. Si loo diyaarin, waxaa lagama maarmaan ah in 85 garaam (kiilo) H ₂ O kala diri 15 garaam (kg) ee alkali.

mass gaws waa hydroxide sodium:

M _NaOH = 23 + 16 + 1 = 40 g / mol.

Hadda waxaan ka heli qadarka hydroxide sodium in xal:

ν = m / M = 15/40 = 0.375 mol.

dareeraha Culayska (biyaha) ee kg:

85 garaam oo H ₂ O = 85/1000 = 0.085 kg H ₂ O in xalka.

Intaas ka dib go'aamisay fiirsashada molal:

Cm = (ν / m) = 0.375 / 0.085 = 4,41 mol / kg.

Iyadoo la tixraacayo dhibaato la mid ah, kuwaas oo lagu xalin karo, iyo in ka badan oo kale si ay u ogaadaan molality iyo molarity.